Abstract : It is well known that the solution of many mathematical problems can be simplified by the use of a carefully selected coordinate system. One example is the numerical treatment of boundary-value problems in partial differential equations. An optimal computational grid for a finite element or a finite difference method should be carefully adapted to the mathematical, numerical, physical and geometrical aspects of the problem. In such a case, one can expect a reduction of numerical errors, a reduction of computing time and, most important, an excellent physical presentation of the results. The present paper describes a grid generation procedure to be applied to transonic flows with interferences. (Author)